We visited the River Walk both days that we were in San Antonio and enjoyed the walk along the river and seeing the sights along and near the river.
The area was nice and clean and although the river was dirty looking, it was interesting to see. The restaurants were numerous and some looked very nice.
I did notice that there are a lot of homeless people in the area resting under the bridges in the river walk area and a few of them drinking out of paper bags. There was no police that I saw moving them along and I do think it should be a priority for the tourist trade.